4 THE ENTOMOLOGIST. 



butyric acid, which has a repulsive odour, though hardly that of 

 putrefaction. 



I do not believe in any method of preventing the formation of 

 grease, unless it be, when rearing larvae, to feed them on a sort of 

 Banting system ; or, with newly emerged imagines, to get them to 

 pair, lay, and fly, — all rather risky proceedings in view of prospec- 

 tive specimens. But there can he little doubt as to the external 

 appearance of grease being delayed in many cases for an indefinite 

 period, it may be for years, and it may be for ever, by keeping 

 the setting-house and cabinets in a cool, dry, well-ventilated 

 room. 



Not having used lime hydrate as an absorbent for grease, 

 I can offer no decided opinion upon its merits, but should 

 imagine that its strong alkaline and somewhat caustic qualities 

 would render it useless for the purpose ; surely magnesia car- 

 bonate is lighter, more absorbent, non-corrosive, and therefore 

 less likely to injure the specimen. Again, these powders only act 

 in a superficial way, they do not extract grease from the interior. 

 To do this, repeated soakintrs in benzine collas or methylated 

 ether, as recommended by Messrs. Arkle, and Christy, and in the 

 case of the latter fluid, by myself (Entom. xxvi. 32, 109, 217; 

 xxvii. 6), should be resorted to in the first instance ; after which, 

 if considered necessary, the powder may be applied. 



There are one or two remarks I should like to offer on the 

 subject of killing, supplemental to Mr. Stafford Chope's paper. 

 Firstly, the burnets appear to be proof against the cyanide 

 bottle ; to use my friend Auld's expression, they positively revel 

 in it ; and my friend Sydney Webb tells me that, in their case, it 

 actually conduces to amativeness, so that when he wants Zygsense 

 to pair, he pops them into the cyanide bottle with the happiest 

 results. Secondly, it is not generally known that a puncture with 

 vinegar is almost, if not quite, as deadly as one with oxalic 

 acid, and of course the agent is of a harmless nature to the 

 operator ; but to me all acids seem to be objectionable. The 

 nicotine from a foul pipe, as suggested, is very effectual, but we 

 are not all smokers ; a strong decoction of tobacco, as used by 

 gardeners, is better. It should be kept in a small phial, to the 

 cork of which should be attached, either a sharp-pointed grooved 

 needle, or a sewing-machine needle ; or, better still, a fine crow- 

 quill steel pen from which one of the nibs has been broken off; 

 an ordinary needle would leave the greater part of the poison 

 outside the insect, and consequently its action would be much 

 diminished. 



Last season I tried a strong tincture of tobacco, mixed with 

 an equal proportion of concentrated infusion of quassia, and it 

 killed quickly ; but until I have tried it more extensively on 

 burnets, I don't like to praise it up too much. Next season, if 

 all goes well, I intend to go collecting burnets ; and if I can find 



